Replace freetext signals (RFR, LGTM, VERDICT: PASS) with YAML frontmatter envelopes routed by a `signal` field. New message-schema skill defines 12 message types covering worker submissions, review/audit verdicts, triage/plan results, research results, and orchestrator commands. All agents load the skill; qa-checklist enforces compliance; orchestrate routes by envelope signal.
- Create .claude/memory/ as canonical project memory location - Add MEMORY.md index and first entry: TODO for inter-agent JSON schema - Document project memory convention in CLAUDE.md (path, format, commit policy)
